X-ray installation in which alpha compressed gas is provided between the tube and an envelope



April 17, 1934. A. BOUWERS 1,954,915

X-RAY INSTALLATION IN WHICH A COMPRESSED GAS IS PROVIDED BETWEEN THETUBE AND AN ENVELOPE Filed April 1, 1931 2 Sheets-Sheet 1 [m an 72x W WPatented Apr. 17, 1934 ars trier:

X-RAY INSTALLATION IN WHICH A COM- PRESSED GAS HS PROVIDED BETWEEN THETUBE AND AN ENVELOPE Albert Bouwers, Eindhoven, Netherlands, assigner toN. V. Philips Gloeilampenfabrieken, Eindhoven, Netherlands ApplicationApril 1, 1931, Serial No. 527,014

In the Netherlands April 36, 1930 Claims.

The present invention concerns an improvement in the X-ray installation,described in my copending application, Serial No. 346,245, filed March11, 1929, with issue date of April 3, 193 1 5 and Patent No. 1,953,391,in which a compressed gas is enclosed between the tube and a closedenvelope surrounding the latter.

In an X-ray installation according to this prior application theenvelope may be connected by means of piping to a pressure pmnp devicewhereby the pressure inside the envelope can be re stored if it hasfallen below the desired value.

The present invention has for its object to avoid such a particularpiping. For this purpose the tube has connected to it a current supplycable provided with a passage which communicates with the spacecomprised between the tube and the envelope. This passage may furthercommunicate with a device which furnishes the gas pressure in the spacesurrounding the tube.

This combination affords the advantage that for restoring the gaspressure no pumping devices or pressure conduits have to be coupled withthe tube. The latter simply utilizes one or more current supply cablesand its exterior does not diifer from that of an installation in whichno use is made of gas pressure between the tube and an envelopesurrounding the latter. If need be, a measuring device or a safetydevice may of course be secured to the envelope. 4

The invention will be more clearly understood by referring to theaccompanying drawings in which Figure 1 represents schematically anX-ray tube connected to a device for the supply of pressure, while acurrent supply cable acts as pressure conduit.

Figure 2 shows in section an example of the manner in which such a cablemay be connected to the envelope of the tube.

' Referring to Figure 1, inside a metal envelope connected to earth isarranged an X-ray tube, which is supplied with high-tension current bycables 2 and 3 connected to the ends of the member 1. The cable 2 leadsto a contact cover 4 secured to a wall and it is thus connected to ahigh-tension transformer not shown in the drawings.

A tubular conduit 5, of insulating material leads from the said contactcover to a cylinder 6 filled with carbonic oxyd, nitrogen or anothersuitable gas of high pressure. The conduit 5 communicates with a passageprovided in the cable 2, said passage communicating with the spacebetween the envelope 1 and the discharge tube enclosed thereby. Thecable 2 consequently supplies both electric current and compressed gas,which furthers the easy movability of the tube for there are noparticular conduits which impede the movement of the tube.

In Figure 2 part of the glass wall 10 of an X-ray tube is visible. In are-entrant portion 11 of this Wall are located current supply conductors12 and 13 leading to the incandescent cathode. The conductor 13 issecured to a bushing 14 5 having attached to it a resilient contactsleeve 15. the conductor 12 being secured to a contact pin 16. Thecurrent is supplied by a cable 17 having two conductors l8 and 19 ofwhich the latter, which has a tubular shape, surrounds the former.Between these two conductors there exists a potential differencesufiicient for heating the cathode. The conductor 18 terminates in acontact sleeve 20 which cooperates with the pin 16 whereas the conductor19 is secured to a sleeve 21 which is resiliently engaged by the sleeve15.

The contact members 20 and 21 are secured to a connecting piece 22 ofsuitable insulating material, which is slid on the end of the cable 17and which is cemented thereto preferably with 0 the aid of a binder suchas shellac so that there is no air between the cable and the conductor19 protruding therefrom and the connecting piece 22. The cable 17 isenclosed by a metal sheath which is electrically connected, through thein- 5 termediary of rings 23 and 24, with the aid of a screw cap 25 tothe metal envelope 26 which entirely surrounds the tube 10. Theconnecting piece 22'fits into a cavity of a block 27 of insulatingmaterial in which are secured the contact members 15 and 16. This blockcloses the end of an insulating cylinder 28 within which the X-ray tube10 is located.

The gas supplied by the hollow conductor 19 can flow through aperturesprovided in spacing 5 rings 29 and 30 into the bushing 14 andsubsequently into the space comprised between the tube 10 and thecylinder 28. More towards the middle of the tube and therefore notvisible in the drawing, said cylinder is pierced with apertures whichestablish the communication between the interior space of the cylinder28 and the space between the cylinder and the envelope 26. The spacebetween the tube and the earthed envelope 26 is thus entirely filledwith compressed 1 gas having a pressure of, for example, 1 atm. aboveatmospheric, said gas being supplied by the hollow cable 17.

What I claim is:

1. In an X-ray installation, an enclosing envelope, an X-ray tubemounted therein and spaced from the wall thereof, said tube beingprovided with lead-in wires, a current-conducting cable comprisingconductors and an insulating covering, said cable extending through anaperture in the envelope, means at said aperture for sealing the spacebetween the cable and the edge of said aperture, means inside of saidenvelope for connecting the insulated conductors of said cable with thelead-in wires of said X-ray tube, said cable being provided with a gaspassage which communicates with the space between the X-ray tube and theenclosing envelope, and means connected to said cable for supplying gasto said space through said passage.

2. In an X-ray installation, a closed metal envelope, an X-ray tubemounted therein and spaced from the wall thereof, said tube beingprovided with lead-in wires, a high-tension cable having acurrent-conducting core and a metal envelope, a device for furnishinggasunder pressure and means connecting the end of said cable remote fromthe tube to said device so as to pro vide communication between saiddevice through said gas passage to the space between the tube andenclosing envelope.

3. In an X-ray installation, a closed envelope, an vX-ray tube providedwith leading-in conductors and contact members secured at the ends Ithereof, said tube being mounted in said closed envelope partially inspaced relation with the wall thereof, a high-tension cable extendingthrough an aperture in saidenvelope and having a duct extendinglongitudinally therethrough and a current-conducting part for conductingcurrent to said X-ray tube, a terminal piece mounted on one end of saidcable and having an axial perforation communicating with the duct insaid cable and the free space in the closed envelope and bearing contactmembers connecting thecurrent conducting part of said cable with thecontact members of the X-ray tube for establishing electrical connectionbetween said current-conducting part and operative parts of said X-raytube,

a tank of compressed gas having better insulating properties than air,means connecting same with the duct in said cable and means adjacent theaperture in said envelope for preventing gas leakage from the enclosingenvelope through the space between the cable and the adjacent edge ofthe envelope.

4. In an Xray installation, an X-ray tube having a filamentary electrodeand leading-in wires, an insulating envelope surrounding said X-raytube, an apertured metal envelope surrounding said insulating envelopeand spaced therefrom to provide space between said insulating envelopeand the metal envelope, the spaces inside and outside said insulatingenvelope being in communication with each other, a high-tension cablehaving a metallic covering and a twin conductor insulated for aconsiderable portion of the operating voltage of the tube from thesurrounding metallic covering, a central duct in said cable, a terminalpiece of insulating material mounted on one end of said cable, saidterminal piece projecting through the aperture in the wall of the metalenvelope and engaging the insulating envelope mounted therein, meansdefining contact members for connecting the conductors of the cable withthe leading-in wires of said tube, one set of contact members belongingto one of the conductors surrounding a set of contact members belongingto the second conductor, the ringshaped space between said two sets ofcontact members communicatingat one side with the space between theX-ray tube and the insulating envelope and at the other side with thecentral duct in said high-tension cable and means in- I 5. Incombination, an enclosing envelope, an

electrical discharge tube mounted therein and spaced from thewallthereof, said tube having leadin wires, a hollow flexible cablehaving conductors for supplying current to the tube and its endextending through said envelope, said conductors being connected to saidlead-in wires, means including said hollow cable for supplying gas tothe space between said tube and said envelope and means for securing theend of said cable to said envelope.

ALBERT BOUWERS.

